/* allocated an indirect block for a vnode who's indirect block is currently sparse */
static int alloc_indirect_block(vnode_t *v){
/* an array of 0's that we'll use to quickly create blocks of zeros */
static int zero_array[BLOCK_SIZE] = {};
s5_inode_t *inode = VNODE_TO_S5INODE(v);
KASSERT(inode->s5_indirect_block == 0);
/* first, get an indirect block */
int indirect_block = s5_alloc_block(VNODE_TO_S5FS(v));
if (indirect_block == -ENOSPC){
dbg(DBG_S5FS, "couldn't alloc a new block\n");
return -ENOSPC;
}
KASSERT(indirect_block > 0 && "forgot to handle an error case");
/* then, zero it */
pframe_t *ind_page;
mmobj_t *mmo = S5FS_TO_VMOBJ(VNODE_TO_S5FS(v));
int get_res = pframe_get(mmo, indirect_block, &ind_page);
if (get_res < 0){
return get_res;
}
memcpy(ind_page->pf_addr, zero_array, BLOCK_SIZE);
int dirty_res = pframe_dirty(ind_page);
if (dirty_res < 0){
return dirty_res;
}
/* finally, set this block to be the indirect block of the inode */
inode->s5_indirect_block = indirect_block;
s5_dirty_inode(VNODE_TO_S5FS(v), inode);
return 0;
}
/*
* s5_seek_to_block:
* Return the disk-block number for the given seek pointer (aka file
* position).
* param vnode: pointer to vnode
* param seekptr: seek offset
* alloc: allocate new page or not
* return: the block number, or negative number on failure
*/
int
s5_seek_to_block(vnode_t *vnode, off_t seekptr, int alloc)
{
KASSERT(vnode != 0);
KASSERT(alloc == 1 || alloc == 0);
KASSERT(seekptr >= 0);
s5_inode_t* inode = VNODE_TO_S5INODE(vnode);
uint32_t block_number = S5_DATA_BLOCK(seekptr);
/* check if the block_number is valid */
if (block_number >= S5_NIDIRECT_BLOCKS + S5_NDIRECT_BLOCKS)
{
return -1;
}
if (block_number < S5_NDIRECT_BLOCKS)
{
/* sparse block */
if (inode->s5_direct_blocks[block_number] == 0)
{
/* alloc is zero, simply return */
if (alloc == 0)
{
return 0;
}
else
{
/* alloc a new disk block */
int block_num = s5_alloc_block(VNODE_TO_S5FS(vnode));
if (block_num < 0)
{
/* error */
return block_num;
}
else
{
/* add the new block to inode */
inode->s5_direct_blocks[block_number] = block_num;
/* dirty the inode */
s5_dirty_inode((VNODE_TO_S5FS(vnode)), inode);
return block_num;
}
}
}
else /* already there*/
{
return inode->s5_direct_blocks[block_number];
}
}
else
{
/* indirect blocks */
/* if the indirect block is zero, alloc it firstly */
pframe_t* page = NULL;
if (inode->s5_indirect_block == 0)
{
int block_num = 0;
if ((block_num = s5_alloc_block(FS_TO_S5FS(vnode->vn_fs))) < 0)
{
return block_num;
}
else
{
int ret = pframe_get(S5FS_TO_VMOBJ(FS_TO_S5FS(vnode->vn_fs)),
block_num, &page);
if (ret < 0 || page == NULL)
{
return ret;
}
else
{
pframe_pin(page);
memset(page->pf_addr, 0, S5_BLOCK_SIZE);
pframe_dirty(page);
pframe_unpin(page);
inode->s5_indirect_block = block_num;
s5_dirty_inode(FS_TO_S5FS(vnode->vn_fs), inode);
}
}
}
else
{
int ret = pframe_get(S5FS_TO_VMOBJ(FS_TO_S5FS(vnode->vn_fs)),
inode->s5_indirect_block, &page);
if (ret < 0 || page == NULL)
return ret;
}
KASSERT(page != NULL);
pframe_pin(page);
int off = block_number - S5_NDIRECT_BLOCKS;
int32_t* addr = ((int32_t*)page->pf_addr) + off;
pframe_unpin(page);
if (*addr == 0)
{
if (alloc == 0)
{
return 0;
}
else
{
int block_num = s5_alloc_block(VNODE_TO_S5FS(vnode));
if (block_num < 0)
{
return block_num;
}
else
{
pframe_pin(page);
*addr = block_num;
pframe_dirty(page);
pframe_unpin(page);
return block_num;
}
}
}
else
{
/* already there, return */
return *addr;
}
}
}
/*
* Return the disk-block number for the given seek pointer (aka file
* position).
*
* If the seek pointer refers to a sparse block, and alloc is false,
* then return 0. If the seek pointer refers to a sparse block, and
* alloc is true, then allocate a new disk block (and make the inode
* point to it) and return it.
*
* Be sure to handle indirect blocks!
*
* If there is an error, return -errno.
*
* You probably want to use pframe_get, pframe_pin, pframe_unpin, pframe_dirty.
*/
int
s5_seek_to_block(vnode_t *vnode, off_t seekptr, int alloc)
{
int block_index = S5_DATA_BLOCK(seekptr);
if ((unsigned) block_index >= S5_MAX_FILE_BLOCKS){
dbg(DBG_S5FS, "file too large");
return -EFBIG;
}
if (seekptr > vnode->vn_len && !alloc){
return 0;
}
s5_inode_t *inode = VNODE_TO_S5INODE(vnode);
uint32_t block_num;
if (block_index >= S5_NDIRECT_BLOCKS){
pframe_t *ind_page;
mmobj_t *mmo = S5FS_TO_VMOBJ(VNODE_TO_S5FS(vnode));
if (inode->s5_indirect_block == 0){
if (!alloc){
return 0;
}
int alloc_res = alloc_indirect_block(vnode);
if (alloc_res < 0){
dbg(DBG_S5FS, "error allocating indirect block\n");
return alloc_res;
}
}
if (pframe_get(mmo, inode->s5_indirect_block, &ind_page) < 0){
panic("an indirect block is messed up\n");
}
block_num = ((uint32_t *) ind_page->pf_addr)[block_index - S5_NDIRECT_BLOCKS];
/* case where we've found a sparse block and need to allocate*/
if (block_num == 0 && alloc){
pframe_pin(ind_page);
int block_num = s5_alloc_block(VNODE_TO_S5FS(vnode));
pframe_unpin(ind_page);
if (block_num == -ENOSPC){
dbg(DBG_S5FS, "couldn't alloc a new block\n");
return -ENOSPC;
}
KASSERT(block_num > 0 && "forgot to handle an error case");
((uint32_t *) ind_page->pf_addr)[block_index - S5_NDIRECT_BLOCKS] = block_num;
int dirty_res = pframe_dirty(ind_page);
if (dirty_res < 0){
return dirty_res;
}
}
} else {
block_num = inode->s5_direct_blocks[block_index];
/* case where we've found a sparse block and need to allocate*/
if (block_num == 0 && alloc){
int block_num = s5_alloc_block(VNODE_TO_S5FS(vnode));
if (block_num == -ENOSPC){
dbg(DBG_S5FS, "couldn't alloc a new block\n");
return -ENOSPC;
}
KASSERT(block_num > 0 && "forgot to handle an error case");
inode->s5_direct_blocks[block_index] = block_num;
s5_dirty_inode(VNODE_TO_S5FS(vnode), inode);
}
}
return block_num;
}
/*
* Return the disk-block number for the given seek pointer (aka file
* position).
*
* If the seek pointer refers to a sparse block, and alloc is false,
* then return 0. If the seek pointer refers to a sparse block, and
* alloc is true, then allocate a new disk block (and make the inode
* point to it) and return it.
*
* Be sure to handle indirect blocks!
*
* If there is an error, return -errno.
*
* You probably want to use pframe_get, pframe_pin, pframe_unpin, pframe_dirty.
*/
int
s5_seek_to_block(vnode_t *vnode, off_t seekptr, int alloc)
{
/* CASE BLOCK TYPE ALLOC Direct Sparse Indirect Sparse WAT DO?
* 1 (BLOCK > Total Blocks) Return Error
* 2 DIRECT FALSE TRUE N/A return block from s5_direct_blocks
* 3 DIRECT TRUE TRUE N/A allocate new block and point inode (also memcpy)
* 4 DIRECT TRUE FALSE N/A return block from s5_direct_blocks
* 5 INDIRECT FALSE TRUE TRUE return 0
* 7 INDIRECT FALSE FALSE FALSE Find block we want
* 8 INDIRECT TRUE FALSE FALSE Find block we want
* 9 INDIRECT TRUE TRUE FALSE allocate new block, memcpy to 0, set data address in indirect
* * INDIRECT TRUE N/A TRUE allocate new block, pframe_get on inode->indirect_block
*/
dbg_print("s5_seek_to_block: Entering Function, seekptr: %i, alloc: %i\n",seekptr,alloc);
s5fs_t* vnode_s5fs = VNODE_TO_S5FS(vnode);
s5_inode_t* vnode_inode = VNODE_TO_S5INODE(vnode);
struct mmobj* vnode_vmobj = S5FS_TO_VMOBJ(vnode_s5fs);
uint32_t data_block = S5_DATA_BLOCK(seekptr);
pframe_t* pf;
dbg_print("s5_seek_to_block: a\n");
if(data_block > S5_MAX_FILE_BLOCKS)
{
/* Case 1 */
dbg_print("s5_seek_to_block: Case 1\n");
return 0;
}
if(data_block < S5_NDIRECT_BLOCKS)
{
dbg_print("s5_seek_to_block: b\n");
/* Direct Block */
if(!alloc)
{
/* ALLOC FALSE */
/* CASE 2 */
dbg_print("s5_seek_to_block: c\n");
dbg_print("s5_seek_to_block: Case 2\n");
return vnode_inode->s5_direct_blocks[data_block];
}
else
{
/* ALLOC TRUE */
dbg_print("s5_seek_to_block: d\n");
if(vnode_inode->s5_direct_blocks[data_block] == 0)
{
/* Sparse Block */
/* CASE 3 */
dbg_print("s5_seek_to_block: e\n");
pframe_get(vnode_vmobj,data_block,&pf);
pframe_pin(pf);
int block_alloc = s5_alloc_block(vnode_s5fs);
dbg_print("s5_seek_to_block: f\n");
if(block_alloc == -ENOSPC)
{
/* Allocation Failure */
dbg_print("s5_seek_to_block: g\n");
pframe_unpin(pf);
dbg_print("s5_seek_to_block: Allocation Failure #1\n");
return -ENOSPC;
}
else
{
/* Success in Allocation, Connect Inode and Dirty */
dbg_print("s5_seek_to_block: h\n");
vnode_inode->s5_direct_blocks[data_block] = block_alloc;
/* memset(pf->pf_addr, 0, PAGE_SIZE); */
pframe_dirty(pf);
s5_dirty_inode(vnode_s5fs,vnode_inode);
pframe_unpin(pf);
dbg_print("s5_seek_to_block: Case 3\n");
return block_alloc;
}
}
else
{
/* Not Sparse Block */
/* CASE 4 */
dbg_print("s5_seek_to_block: Case 4\n");
return vnode_inode->s5_direct_blocks[data_block];
}
}
}
else
{
/* Indirect Block */
dbg_print("s5_seek_to_block: i\n");
if(!alloc)
{
/* ALLOC FALSE */
dbg_print("s5_seek_to_block: j\n");
if(vnode_inode->s5_indirect_block == 0)
{
/* Sparse Block */
/* CASE 5 */
dbg_print("s5_seek_to_block: Case 5\n");
return 0;
}
else
{
/* Not Sparse Block */
/* CASE 7 */
dbg_print("s5_seek_to_block: Case 7\n");
return vnode_inode->s5_direct_blocks[data_block - S5_NDIRECT_BLOCKS];
}
}
else
{
/* ALLOC TRUE */
dbg_print("s5_seek_to_block: k\n");
if(vnode_inode->s5_indirect_block == 0)
{
/* Sparse Block */
/* CASE 5 */
dbg_print("s5_seek_to_block: l\n");
int indirect_alloc = s5_alloc_block(vnode_s5fs);
if(indirect_alloc == -ENOSPC)
{
/* Allocation Failure */
dbg_print("s5_seek_to_block: Allocation Failure #2\n");
return -ENOSPC;
}
/* Success in Allocation, Connect Inode and Dirty */
dbg_print("s5_seek_to_block: m\n");
pframe_get(vnode_vmobj,vnode_inode->s5_indirect_block,&pf);
pframe_pin(pf);
/* memset(pf->pf_addr, 0, PAGE_SIZE); */
vnode_inode->s5_indirect_block = indirect_alloc;
pframe_dirty(pf);
s5_dirty_inode(vnode_s5fs,vnode_inode);
dbg_print("s5_seek_to_block: n\n");
}
else
{
/* Not Sparse Block */
dbg_print("s5_seek_to_block: o\n");
pframe_get(vnode_vmobj,vnode_inode->s5_indirect_block,&pf);
pframe_pin(pf);
}
dbg_print("s5_seek_to_block: p\n");
uint32_t indirect_map = data_block - S5_NDIRECT_BLOCKS;
uint32_t* block_array = (uint32_t*)pf->pf_addr;
int direct_index = block_array[indirect_map];
if(direct_index == 0)
{
dbg_print("s5_seek_to_block: q\n");
direct_index = s5_alloc_block(vnode_s5fs);
if(direct_index == -ENOSPC)
{
/* Allocation Failure */
dbg_print("s5_seek_to_block: Allocation Failure #3\n");
return -ENOSPC;
}
}
dbg_print("s5_seek_to_block: rn");
block_array[indirect_map] = direct_index;
pframe_dirty(pf);
pframe_unpin(pf);
dbg_print("s5_seek_to_block: Case 6\n");
return direct_index;
}
}
/* NOT_YET_IMPLEMENTED("S5FS: s5_seek_to_block");
* return -1;
*/
}
